The present invention relates to wheel assemblies for use on luggage and, more particularly, to shock absorbing wheel assemblies that inhibit transfer of external shocks to delicate equipment within the luggage.
Electronic equipment, such as computers, printers, telephones, personal digital assistants, stereo equipment, test equipment, video cameras, and the like, is commonly made in portable form. Although portable electronic equipment is designed to be transported, care must be taken during transportation, and damage to such equipment may occur if external shocks are applied the equipment such as by dropping, jostling, or rough handling. Accordingly, portable electronic equipment is commonly transported in a padded bag to absorb such external shocks.
The present invention is of particular relevance when applied to the transportation of relatively large, heavy, and expensive electronic equipment such as portable computers, and that application will be described herein in detail. However, the present invention may have broader application to other delicate items of similar size and weight such as glassware, artwork, and the like. Accordingly, the scope of the present invention should be determined by the claims appended hereto and not the following detailed description.
A portable computer is commonly carried in a bag or case approximately the size of an oversized briefcase having padding material sewn into the exterior panels thereof. The padding material is commonly a resilient material such as foam that compresses when a force is applied but which expands to its original size and shape when the force is removed. For many external shocks, the padding material is sufficient to protect the computer within.
In addition, conventional computer bags or cases are often somewhat oversized, with an inner compartment for the computer and one or more outer compartments for paper material and less delicate or expensive equipment. The bulk of such multi-compartmented bags or cases also helps to protect a computer in the inner compartment because the collapsing of the external panels and the material in the outer compartments will absorb external shocks.
A class of computer bags even provides a separate internal cover that is padded and closely conforms to the outer dimensions of the computer. This internal cover is suspended within the outer, main bag or case by a resilient suspension system. The suspension system allows the internal bag or case to move within a narrow range of movement while resiliently opposing such movement. Such a suspension system is particularly effective at absorbing the shock of being dropped on a bottom edge panel.
In the last several years, wheeled luggage has become commonly available and popular in the marketplace. Wheeled luggage commonly comprises two wheel assemblies attached to a bottom edge panel of the bag and a retractable handle assembly that extends up from the top edge panel of the bag. The wheels are relatively unobtrusive, allowing the bag to be carried like a conventional suitcase with the handle assembly retracted when desired. When the bag is transported with the assistance of the wheels, the handle assembly is extended out and the bag is tipped slightly forward and pulled along with a forward face panel in front.
This type of wheeled luggage is popular because the user need not carry the entire weight of the luggage and its contents. The wheel assemblies employed by such wheeled luggage have been applied to computer bags or cases.
However, the Applicant has recognized that this type of wheel assembly has created a new class of potentially damaging shocks that may be transferred to the computer or other delicate electronic equipment within the bag or case. In particular, rolling the wheeled computer bag over a bumpy or uneven surface or up curbs may create vibrations and/or minor shocks that can damage delicate equipment. The need thus exists for improved wheeled bags that protect computers or other delicate equipment within when the bags are rolled along the ground.
A professional patentability search conducted on behalf of the Applicant uncovered the following U.S. Pat. No. 5,873,439 to Liang; U.S. Pat. No. 5,873,154 to Chou; U.S. Pat. No. 5,758,752 to King et al.; U.S. Pat. No. 5,778,488 to Tsai; and U.S. Pat. No. 501,706 to Curtis.
U.S. Pat. No. 5,873,154 to Chou discloses a wheel assembly designed to be used with luggage that allows resiliently opposed movement of the wheel to absorb shocks and the like. This wheel assembly appears to be used in a set of four wheels that are all intended to engage at the ground at the same time. This would not be directly applicable to a bag in which the wheel assemblies are located on one edge of a bottom of a suitcase to bear the entire weight when the suitcase is tilted forward and rolled.
In addition, the Chou patent discloses the use of a wheel holder seat pivotably mounted onto a main seat. The wheel holder seat is in one embodiment substantially horizontal and in another embodiment (FIG. 8) to extends at an angle of about 30 to 40 degrees from horizontal. In both of these arrangements, it would be possible for dirt, rocks, and the like to lodge the area between the wheel holder seat and main seat to prevent movement of the wheel holder seat. This arrangement also requires a push rod which acts on the spring. This push rod resides in a channel which also creates the opportunity for friction and, under dirty conditions, unreliable movement of the push rod.
The Applicant believes that the remaining patents turned up in the search are less relevant than the Chou patent.
U.S. Pat. No. 5,778,488 to Tsai discloses a spring loaded retractable wheel. When a load is applied to the suitcase, the wheel moves into a retraction position in which the weight of the bag is born by the wheel. When the weight of the bag is removed from the wheel, a spring is configured to return the wheel to a retrieved position. This arrangement does not result in absorption of shocks by the spring, but instead simply moves the wheel into a retrieved position when the weight of the bag is not born by the wheel.
U.S. Pat. No. 5,873,439 to Liang discloses a supporting device for a wheeled suitcase. The suitcase is conventional in that it has a wheel along one edge of the case. A leg member may be rotated out to form a tripod that bears the weight of the suitcase. The leg member is detachably attached to the back of the suitcase when not in use.
U.S. Pat. No. 5,758,752 to King et al. discloses a retractable wheel for a bag. The wheel employs a spring to assist in moving it between two positions but does not absorb shocks in either of these positions.
U.S. Pat. No. 501,706 to Curtis patent discloses a hand truck or dolly having spring that attaches its lower ends to a wheel axial.
The Applicant is also aware of U.S. Pat. No. 5,217,119, which discloses a computer bag having an integral suspension systems. This patent does not disclose the use of wheel assemblies to facilitate transportation of the bag.
The present may be embodied as a wheel assembly for supporting a bag that is tilted and pulled along a surface. Such a wheel assembly comprises a wheel housing, a strut member, a spring member, and a wheel member. The wheel housing is rigidly attached to a bottom edge of the bag. The strut member is mounted within the housing for movement between first and second positions. The spring member is arranged between the wheel housing and the strut member to oppose movement of the strut member from the first position to the second position. The wheel member is rotatably attached to the strut member such that at least a portion of the wheel member extends out of the wheel housing as the strut member moves between the first and second positions. The wheel member engages the surface and rotates to allow the bag to roll along the surface when the bag is tilted and pulled. The strut member is substantially vertically aligned when the bag is tilted and pulled and when the strut member moves between the first and second positions.
The present invention may also be embodied as method of supporting a bag as the bag is tilted and pulled along a surface. In this case, the method comprises the steps of rigidly connecting a wheel housing to a bottom edge of the bag. A strut member is mounted within the housing for movement between first and second positions. Movement of the strut member from the first position to the second position is opposed by arranging a spring member between the wheel housing and the strut member. A wheel member is rotatably attached to the strut member such that at least a portion of the wheel member extends out of the wheel housing as the strut member moves between the first and second positions. The bag is tilted such that the wheel member engages the surface and the load of the bag is transmitted at least partly from the wheel housing to the strut member through the spring member. The housing member and the strut member are configured such that the strut member is substantially vertically aligned when the bag is tilted and when the strut member moves between the first and second positions.
The present invention may also be embodied as a bag assembly that is adapted to be tilted and pulled along a surface. In this case, the bag assembly comprises a bag, a handle assembly, and first and second wheel assemblies, The bag defines top and bottom edges. A handle assembly is mounted to the top edge of the bag. The first and second wheel assemblies are mounted to the bottom edge of the bag. Each of the wheel assemblies comprises a wheel housing, a strut member, a spring member, and a wheel member. The wheel members engages the surface and rotate to allow the bag to roll along the surface when the bag is tilted and pulled. The strut members are substantially vertically aligned when the bag is tilted and pulled and when the strut members move between the first and second positions.